vpe-sitter 0.2.1

Introduction

This library is a plugin for VPE.

Tree-sitter is an incremental parsing library that is intended to be fast enough to be integrated into text editors in order to provide syntax aware tooling. One obvious use is as a mechanism to implement syntax highlighting, which is the primary reason that this library exist; i.e. to support VPE_Syntax.

This library provides a mechanism to associate a Tree-sitter parse tree with any buffer that displays a supported language. Client code of this library can register to receive callbacks whenever the tree has been updated.

The following example demonstrates the main parts of the API. First tree-sitter must be enabled for a buffer.

import vpe
import vpe_sitter
from vpe import vim
from vpe_sitter.listen import Listener, ConditionCode, AffectedLines

# Try enabling tree-sitter for the current buffer.
if msg := vpe_sitter.treesit_current_buffer():
    # Not possible for this buffer. Most likely because the buffer's
    # filetype is not a supported language.
    vpe.error_msg(msg)
else:
    buf: vpe.Buffer = vim.current.buffer
    listener: Listener = buf.store('tree-sitter').listener

Multiple clients can do this, they will all share the same Tree-sitter Listener instance. The client will need to provide a callback function along the lines of:

def handle_tree_change(
        code: ConditionCode, affected_lines: AffectedLines) -> None:
    """Handle a tree change notification.

    The affected_lines parameter is a list of Python ranges.
    """
    match code:
        case ConditionCode.NEW_CLEAN_TREE:
            # A new tree that matches the buffer is available.

        case ConditionCode.NEW_OUT_OF_DATE_TREE:
            # A new tree is available, but the buffer changed during
            # parsing.

        case ConditionCode.PENDING_CHANGES:
            # Changes to the buffer have been detected and a new parse tree
            # will be generated shortly.

You can then register for callbacks using the Listener instance.

listener.add_parse_complete_callback(handle_tree_change)

Client code will typically have to use the generated Tree-sitter Tree instance, which is available as the Listener.tree property. See the Tree-sitter Tree documentation for the API available to client code. Be warned that this link points to the documentation for the latest Tree-sitter Python bindings, not the ones use by this library. Watch this space for online documentation that will define a version correct API for Tree object.